Return to Contents Chapter 15: Alcohols, Diols and Thiols Ch 15 contents

Oxidative Cleavage of Diols

periodic acid cleavage of 1,2-diols

Reaction type: Oxidation-reduction


  • 1,2- or vicinal diols are cleaved by periodic acid, HIO4, into two carbonyl compounds.
  • The reaction is selective for 1,2-diols.
  • The reaction occurs via the formation of a cyclic periodate ester (see right).
  • This can be used as a functional group test for 1,2-diols.
  • The products are determined by the substituents on the diol.
Can you recall a reaction that forms carbonyl groups via cleavage of an alkene ? ANSWER
How are 1,2-diols made from alkenes ? ANSWER
What are the oxidation states of the iodine in HIO4 and HIO3ANSWER
The mechanism is not trivial, so attention here is focussed on the actual cleavage step. Prior to this, the alcohol reacts to form a cyclic periodate ester (shown). The periodate ester undergoes arearrangement of the electrons, cleaving the C-C bond, and forming two C=O. periodate cleavage of 1,2-diols

previous page
next page
organic chemistry © Dr. Ian Hunt, Department of Chemistry University of Calgary